I am using Data Envelopment Analysis for my research. Most of the inputs and outputs are derived from the past literature. However I want to test some additional factors which may be considered as Input or Output factor. I read about the 3-level fractional factorial design as suggested by Hiroshi Morita and Necmi K Avkiran in their 2008 paper "Selecting Inputs and Outputs in Data Envelopment Analysis by designing statistical experiments".
1. Can somebody provide clarifications on how to use this approach?
2. Is there any other approach to choose inputs and outputs?